feat(cmd): Add build Command to CLI Tool

[jshlbrd]

Description

• Adds substation build to the CLI tool

Motivation and Context

This replaces the build shell script and follows the conventions of other CLI tool commands (mimicking the go tool).

These readme.com docs need to be updated for the v2.2.0 release:

• https://substation.readme.io/docs/builds (this no longer exists)
• https://substation.readme.io/docs/app-substation (update for new commands)
• https://substation.readme.io/docs/try-substation-on-macos-linux (replace reference to compile.sh)

How Has This Been Tested?

substation build was integration tested for a variety of use cases:

• Building individual files
• Building directories
• Building nested directories

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.

[shellcromancer]

Only blocking change is on the comment for compileFile 👍